The invention relates to a sign comprising a rear plate having at least two sections arranged in a row and a front plate movably arranged in front of the rear plate so that the front plate may be caused to cover or uncover one or more sections.
Such a sign is known from e.g. DE-01-295 16 232 which shows a sign comprising a rear plate with two printed messages, a transparent cover plate and a front plate movably arranged between the rear plate and the cover plate. The rear plate is provided with two printed messages--"Unoccupied" and "Occupied"--and the movable front plate has a size such that it covers one message in its one extreme position, while it covers the other message in its other extreme position.
Another sign is known from U.S. Pat. No. 5,255,462. This sign comprises a front plate, a rear plate and a movable indicator plate. At one end the movable indicator plate has printed thereon an arrowhead which points in a direction opposite to an arrowhead printed at the other end of the indicator plate. The movable indicator plate is provided with a handle so that it may be placed in a position in which it is covered completely by the front plate, where just one arrowhead is visible, while the other is covered by the front plate, and vice versa. A line is printed on the front plate so that the sign can show either just a line or one of two oppositely directed arrows.
Known are also signs where a movable element may be caused to cover one message, while another message is exposed, see e.g. U.S. Pat. No. 4,217,713 and U.S. Pat. No. 4,654,990.
It is common to these signs that the movable element can be moved only in one dimension and can thereby just either expose a first message or a second message, depending on whether the movable element is in its one extreme position or its other extreme position.